This invention relates to an apparatus for the assembly of radial tire components, and more particularly, to an automatic first stage carcass transfer apparatus which can respond to the completion of an automatically built first stage carcass, and transfer such carcass into position on an assembly drum for assembly with a belt-tread stock package, or second stage assembly. In this final two-stage assembly step the belt-tread stock package is attached to and consolidated with a carcass which is previously assembled on a first stage assembly machine.
When applying the two-stage method of assembling a modern radial tire, it is common to use a first stage carcass assembly machine and a second stage machine on which the carcass from the first stage is chucked by its beads and then transformed from a cylinder into a toroidal shape, at which time the belt-tread stock package is added to the carcass, and the assembly is then consolidated by stitching the two tacky subassemblies together.
The basic elements of a modern radial ply pneumatic tire consist of an inner liner, one or more plies, sidewalls, beads, fillers and other bead reinforcements, all of which, when properly assembled, form an assembly called a first stage carcass, as well as a belt-tread stock assembly comprising one or more belts incorporating steel cord or other suitable cord materials and a length of tread stock combined to form a belt-tread stock package or second stage assembly. The first stage carcass and the belt-tread stock package are then combined into a green tire, which is subsequently molded and cured in a vulcanizer.
One form of apparatus for combining the two assemblies is described in U.S. Pat. No. 4,402,782 issued Sept. 6, 1983, to the assignee of this application. The two major assemblies are produced on two distinct and separate types of apparatus which are then combined into a so-called green tire.
The carcass is initially cylindrical and consists of one or more body plies of rubber coated cord, a pair of axially spaced parallel bead rings, layers of the ply material which encompass the bead rings, and side wall stock material. These tire elements are typically assembled in a manually operated apparatus, such as disclosed in U.S. Pat. No. 4,333,788, and consolidated on a cylindrical carcass building drum into the shape of a cylinder. Then the cylindrical carcass is loaded, in most cases manually, onto a tire building or assembly drum (FIGS. 18 and 19 of said U.S. Pat. No. 4,402,782) and re-shaped into a toroidal carcass.
The second assembly is prepared by consolidating one or more relatively nonextensible belts, of suitable cord (e.g. steel wire in the case of a steel belted tire) incorporated into uncured rubber stock, with a band of tread stock. Then the belt/tread stock assembly is consolidated with the toroidal carcass, producing a finished green radial tire carcass which is removed from the building machine and placed in a suitable mold for final shaping and vulcanization of the various rubber components, thereby forming a completed cured tire.
The removal of the carcass from the cylindrical carcass building drum is a manual operation, carried out by the operator of the first stage or carcass assembly apparatus, while the loading of the carcass onto the tire assembly drum of the second stage machine is also a manual operation, carried out by the operator of that machine.
These operations, however, at the present time do not follow each other in quick succession; carcasses are always placed onto carcass handling and storage devices, and they are kept there until needed in scheduling the work of the second stage equipment. Obviously, carcasses waiting for further processing must be handled, stored, and carted about; such operations are costly due to the additional labor and large amount of floor space requirements, but above all, the handling and storage of carcasses adds many uncontrollable and undesirable process variables to the product, such as exposure to touching by human hands and associated exposure to dirt, grease, perspiration, remnants of soap or detergents or skin creams. In addition, there is an undetermined exposure to airborne particles which deposit on the outer surface of the carcasses. The unknown duration of that exposure, anywhere from one hour to three or four days (on long weekends), results in undesirable distortions and carcass deformations.
Thus, it is highly desirable to minimize the various problems, as recited, by eliminating the various manual carcass removal, handling, and reloading operations, and to mechanize these functions.